Sardine decides to see his e-mail friend Guppy whom he falls in love with. When Sardine notices a girl named Iwana he falls in love and follows her thinking that she might be Guppy. Just then, a small monster named Courier appears and Sardine accepts his offer to deliver Sardine's love letter. Later, everyone in school is also interested in Courier and things get out of control when they want to use him to deliver their love letters although they failed to notice that Courier can split into many clones of himself whenever he gets nervous...